The dielectric properties and the relaxation phase transition of copper substituted ferroelectric ceramics

The dielectric properties and the relaxation phase transition of Sr1−xCuxBi2Nb2O9 (SCBN) ferroelectric ceramics prepared by a solid-state process, with x ranging from 0.0 to 0.6, are reported. The microstructure of SrBi2Nb2O9 (SBN) was clearly influenced by Cu2+ substituting the Sr2+ of SBN, as observed by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). An obvious enhancement in dielectric constant was observed and the frequency stability was enhanced for copper substituted SBN compared to SBN. At the same time, the sintering temperature of SBN was reduced significantly by approximately 80 ∘C because of the copper ions being introduced. The maximum dielectric constant peak broadened gradually with increasing copper content, indicating that the phase transition from a normal ferroelectric to a relaxor ferroelectric occurs in SBN.